Start reading from page 93 of the owners manual:
http://www.sonido-7.com/d8b/files/userg ... Bv5_OM.pdfThat will explain how to to set the controls on the D8B to communicate with your DAW. And that brings up this question: what DAW software are you running on your Mac?
I can't tell how much you know about your system from what you write and I can see that English is not your native language...so I don't know how much patient help I can offer because of the language barrier difficulty.
Start with the manual and see what's in your DAWs manual on the subject of external midi control.
I'm assuming you have the console connected and working with your Mac and RME as far as passing audio in and out of your DAW and want to use the D8Bs faders, pans, mute and solo to control the DAWs faders, pans, mutes and solos.